NEW YORK (CBS Newspath) – A federal judge says that Subway could be sued for misleading customers.

The judge says that Subway’s claims about its tuna offerings could be the subject of misleading customers about what is exactly in their sandwiches. This includes a claim that the sandwich chain uses other types of fish, as well as chicken, pork, and cattle. This is all while they advertise that they only use 100% tuna.

The judge called it premature to accept Subway’s argument that any presence of non-tuna DNA might result from eggs in mayonnaise or contact with other ingredients. The judge also rejected the plaintiff’s argument that “reasonable consumers” would expect only tuna in their sandwich.

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In a statement, Subway said it “serves 100% tuna” and is confident it will prevail in the lawsuit.